This invention relates to an operational control for a ventilation, heating, or air conditioning unit of a vehicle, that can be actuated by a turn knob which engages a gearwheel or a disk having a guiding groove, or which itself has the guiding groove, whereby an adjusting lever for actuating a Bowden cable is pivotally mounted at a housing pivot bearing with a guide pin extending into the guiding groove for following the groove.
German patent document (DE 34 34 302 C3), for example, discloses an operational control of this type, wherein a rotating gearwheel works in concert with an adjusting lever that can pivot through a limited angular area about a pivot bearing of a main body for activating--in a pulling sense--a Bowden cable, with the gearwheel having a guiding groove and the adjusting lever being a one-armed, or simple, lever that is pivotally mounted at one end so that its pivot pin can pivot at the pivot bearing of the main body and is linked to the Bowden cable at the other end, the adjusting lever having a guide pin between the pivot pin and the Bowden cable that cooperates with the guiding groove of the gearwheel.
As this publication discloses, the pivot pin and guide pin should be molded onto the adjusting lever; according to the drawing, the adjusting lever has embedded pins (FIG. 6).
Thus the adjusting lever can be designed as a die-cast part to include both pins, or as a punched-out sheet part with embedded pins.
The die-cast part is made of a low-strength alloy that can be pressure-injected, so that the pins, at least, must be large enough to withstand the adjusting forces.
This reduces an angular area of adjustment and increases friction, unlike small pins.
Owing to the large number of parts, the thusly constructed adjusting lever is expensive and prone to failure.
Thus, it is an object of this invention to design an operational control of the type indicated above, wherein smooth adjustment can be achieved while an angular area of adjustment is increased and costs are reduced.